The three things necessary for life to evolve in the universe are liquid water, an abundant source of heat, and organic material. Liquid water is the main source of replenishment for organisms such as plants and animals. It's also the component that's contained in the structure of most organisms. An abundant source of heat is extremely important for life to form and evolve. This is a crucial because without heat, the climate of the area that contains life will be too harsh for organisms to survive. Heat is also important because it aids in the growth of organisms like plants. Organic material is vital for life to evolve because almost every being has its own diet, and a variety of nourishment is always important for homeostasis.
We should consider Earth as permanently isolated from any other planet with intelligence because fossil records show that the cooling Earth developed bacteria when conditions permitted it too.
The Earth may have received the bacteria from meteorites heading for Earth from Mars asteroids. This is probable because Mars has a very low gravity level, and 10% of meteors ejected from Mars hits the Earth. It would be very rare to find two other planets like Mars and Earth in a situation like that. So if this is true, the inhabitants of Earth are lucky that God made the circumstances the way they were, or else we would never be here.
SETI is a government agency and CSETI is not a government agency. "The SETI Institute is a nonprofit corporation founded in 1984. The Institute is a scientific and educational organization governed by the provisions of Section 501(c)(3) of the U.S. Internal Reve Code. The mission of SETI Institute is to explore, understand and explain the nature and prevalence of life in the universe.